Medical instrument for phacoemulsification

ABSTRACT

A medical instrument for phacoemulsification with which the biological tissue of a lens of the eye is comminuted by the introduction of energy, the comminuted product is sucked out through an incision in the cornea, while intraocular pressure is maintained by supplying an irrigating liquid. In an instrument of the type mentioned above, two cannulas are provided for sucking out the ablated lens material and for supplying the irrigating liquid and are connected, via feed lines, with the suction device and with the supply device. A switchable directional valve is provided in the feed lines between the cannulas and the suction device and supply device, by means of which, in a first valve position, a first cannula is connected with the suction device and the second cannula is connected with the supply device and, in a second valve position, the second cannula is connected with the suction device and the first cannula is connected with the supply device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is directed to a medical instrument forphacoemulsification with which the biological tissue of a lens of theeye is comminuted by the introduction of energy, the comminuted productis sucked out through an incision in the cornea, while intraocularpressure is maintained by supplying an irrigating liquid.

2. Discussion of the Relevant Art

For purposes of carrying out the above-mentioned operation, the knownprior-art instruments have a supply cannula for the irrigating liquidand a suction cannula for the core and core fragments. In conventionalmethods for phacoemulsification, a cannula is inserted into the eye tosuck out the cataractous lens core in its entirety. However, thismethod, known since 1967, can be advantageously applied only for softlenses.

With hard cores, the lens material is first comminuted by supplyingenergy, preferably via ultrasound or laser, and the small fragments arethen sucked out through the suction cannula which is enclosed by ahandpiece. The volume of liquid and lens fragments sucked out of theanterior chamber is compensated by an infusion of rinsing liquid intothe anterior chamber via the supply cannula, so that intraocularpressure is substantially maintained.

The supply of liquid, known as irrigation, is carried out in all knownhandpieces via a supply cannula which is constructed as a sleeve that isfitted over the suction cannula. During the operation, the liquid flowsbetween the suction cannula and the inner wall of the sleeve to thedistal end of the handpiece, where two outlet openings are generallyprovided

The introduction of energy is currently carried out by ultrasound inmore than 90% of cataract extractions. It is disadvantageous that theintroduction of ultrasound into the tissue involves unwanted generationof heat, so that cooling must be carried out in order to prevent damageto healthy tissue. To this extent, the sleeve serves a dual function inultrasound phacoemulsification in that the liquid flowing between thesuction cannula and inner wall of the sleeve is utilized for cooling atthe same time. For this reason, handpieces for phacoemulsification usingultrasound technology are, in principle, constructed only withintegrated supply cannula, suction cannula and integrated ultrasoundconductor.

Because of the need to supply liquid and the formation of the sleeve asa cooling element, the distal end of the handpiece is necessarilyrelatively large. Accordingly, the suction cannula, for example, whichitself has a diameter in the range of 0.8 mm to 1.3 mm, is enlarged to adiameter of about 2.5 mm through the use of the sleeve which is drawnover it. In order to introduce a cannula with these dimensions into thetissue, an incision on the order of 3 mm to 3.2 mm is necessary.

However, large incisions of this kind result in loss of aqueous humorand rinsing solution during the operation. Further, the risk ofastigmatism induced by the operation increases as the size of theincision increases. Visual rehabilitation also progresses relativelyslowly with incisions of this size compared to smaller incisions.

For this reason, medical efforts are directed to increasingly smallerincisions with the purpose of introducing injectable lenses into theanterior chamber through these small incisions. However, it is necessaryfor this purpose that the comminuted lens material can be sucked outthrough small incisions and that irrigating liquid can be suppliedthrough the same.

Further, laser phacoemulsification is known from the prior art in whichenergy is introduced via laser radiation which is aimed directly on thetissue to be comminuted. A laser wavelength with a very small depth ofpenetration into the aqueous matter in the interior of the eye must beselected; wavelengths in the low UV range and infrared range are suitedto this purpose. In this connection, the use of Er:YAG lasers with awavelength of λ=2.9 μm has proved successful. In this way, aquasi-nonthermal introduction of energy is achieved and the problemsarising from the use of ultrasound with respect to heat generation nolonger occur.

However, the handpieces known from the prior art for laserphacoemulsification likewise have the disadvantage that the supplycannula, suction cannula and energy supply (for example, vialight-conducting fibers) are integrated in a handpiece and the outletsare spatially oriented to a common area. This also requires a largeincision through which the supply of irrigating liquid and laser energyand the aspiration of comminuted core material must be carried out.

OBJECT AND SUMMARY OF THE INVENTION

On this basis, it is the primary object of the invention to provide amedical instrument for phacoemulsification by which it is possible toreplace the lens through small incisions in the cornea while maintainingthe advantageous quasinonthermal introduction of energy.

According to the invention, this object is met in a medical instrumentfor phacoemulsification with which the biologcal tissue of a lens of theeye is ablated by the introduction of energy, the ablated product issucked out through an incision in the cornea and the intraocularpressure is maintained by supplying an irrigating liquid. The instrumentcomprises two cannulas for sucking out the ablated lens material and forsupplying the irrigating liquid. At least one device is provided for theintroduction of energy through laser radiation. The two cannulas areenclosed by separate handpieces which are movable relative to oneanother. One of the handpieces with the first cannula communicates witha suction device via a feed line. The other of the handpieces with thesecond cannular communicates with a supply device for the irrigatingliquid via another feed line.

With the medical instrument suggested according to the invention, it ispossible to carry out phacoemulsification through small incisionsresulting essentially in the advantages that the risk of inducingastigmatism is now only slight, a quicker postoperative visualrehabilitation is also possible and a lens can now be introduced intothe eye through injection in an accessible phacoemulsificationtechnique.

In this connection, a highly preferred application of the instrumentsuggested according to the invention consists in that after thecomminuted core material is sucked out via one of the two handpieces orvia the cannula integrated in the respective handpiece, the substance isinjected, remains in the eye and replaces the old eye lens.

For this purpose, in constructional variants of the invention, thehandpieces or the cannula are outfitted with connections forcorresponding instruments for introducing a substance of this kind,e.g., for injection or the like.

In another preferred constructional variant, each of the two handpiecesis provided for sucking out the comminuted core material and forsupplying rinsing liquid. For example, when the cannulas of bothhandpieces are displaced with their distal end from opposite sidestoward the lens of the eye, it is possible in this way to carry out thecomminution of tissue as well as aspiration of the ablated productsselectively and alternately in both of these opposite positions.

Compared with one-sided aspiration, this has the advantage that thecannula need not be introduced as deeply, which in turn fits in with thestriving for small incisions and gentle treatment of tissue. For thispurpose, both handpieces are connected, via transport lines or feedlines, to a switchable directional valve by means of which the flowdirections can be reversed when sucking out the ablated product and whensupplying the rinsing liquid. This switching can be carried outadvantageously with a foot switch.

In this connection, it can further be provided that both handpieces areoutfitted with fiber tips for supplying laser energy. The fiber tips canpreferably be arranged inside the cannula and can also be arranged so asto be displaceable inside the cannula in the radiating direction of thelaser energy and in the flow direction. This results in the advantagethat the fiber tip can then be retracted from the treatment site, forexample, when no laser energy is being radiated during irrigation. Theoutlet end of the respective cannula, in contrast to the fiber tip,remains directly at the treatment site.

In another very preferred construction of the invention, it is providedthat a device for eliminating clogging within the cannula or within thefeed lines is associated with one or both of the handpieces. This devicecan have, for example, a cleaning element which can be insertedlaterally into the cannula and/or into one of the feed lines and whichis displaceable within the respective line cross section. This cleaningelement can be, for example, a flexible rod outfitted with a thickenedend or a cleaning spiral whose diameters are adapted to the line crosssection.

Another advantageous construction consists in that one or both of thehandpieces is/are outfitted with auxiliary instruments for holding,gripping, turning, pushing, cutting, splitting, protecting and/orilluminating the tissue at the treatment site. These auxiliary elementsare preferably interchangeable and can be connected with the respectivehandpiece, for example, via an attaching mechanism. In this connection,further constructions are possible in which the auxiliary instrumentscan be retracted into the handpiece via a displacing mechanism or arearranged so as to be displaceable on the outside of the handpiece, sothat they can be moved into the appropriate use position, as needed, atany time.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained more fully in the following withreference to two embodiment examples. The accompanying drawings show:

FIG. 1 a schematic view of a first embodiment example;

FIG. 2 an enlarged section from FIG. 1;

FIG. 3 a schematic view of a second embodiment example; and

FIGS. 4a-4 c a selection of auxiliary instruments.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In a first embodiment example according to FIG. 1, an eye lens 2 whichis covered by a cornea 1 and which is to be extracted by means of thearrangement according to the invention is shown schematically. For thispurpose, a cannula 3 and a cannula 4 are inserted through incisions inthe cornea 1 from approximately opposite directions into the anteriorchamber of the eye as far as the eye lens 2. Further, it will be seenfrom FIG. 1 that cannula 3 is associated with a handpiece 5 and cannula4 is associated with handpiece 6.

Further, FIG. 1 shows that the handpiece 5 and, along with it, thecannula 3 is connected to an irrigating-aspirating unit 9 via a feedline 7, for example, a flexible tube, and via a suction pump 8.Analogously, the handpiece 6, and accordingly the supply cannula 4, isconnected via a feed line 10 to an infusion pump 11 which is coupled inturn with the irrigating-aspirating unit 9.

As is shown in a magnified view in FIG. 2, the cannula 3 has an outletopening 12 which is inclined at an angle α≠90° in the suction direction.A fiber tip 13 is enclosed by the outlet opening 12 and is connected,via coupling optics (not shown in the drawing) provided inside thehandpiece 5, to a light-conducting fiber 14 which is connected in turnto a laser unit (also not shown in the drawing). This laser unitpreferably contains an Er:YAG laser as radiation source. The laserradiation is guided from the laser source via the light-conducting fiber14 and is provided at the light exit face 15 of the fiber tip 13 forradiating into the core material.

The light exit face 15 can be oriented at right angles to the suctiondirection; however, it is also possible for the light exit strip 15 tobe constructed at an inclination to the suction direction.

At the start of the cataract extraction, the inclined outlet opening 12of the cannula 3 is initially inserted into the anterior chamber of theeye and the irrigating-aspirating unit 9 is controlled, so that thesuction pump 8, the infusion pump 11 and the laser unit are put intooperation. Laser energy is radiated into the core material andcomminutes the latter by portions. The fragments are sucked out throughthe outlet opening 13, the suction cannula 3 and the feed line 7.

In order to prevent a reduction in the intraocular pressure when suckingthe liquid and lens fragments out of the anterior chamber, a rinsingliquid which has been introduced 4 from the opposite side in themeantime is provided by the irrigating-aspirating unit 9 via theinfusion pump 11 and the feed line 10. The pressure is maintained withinthe anterior chamber by supplying liquid.

Due to the local separation of the cannula 3 and cannula 4 according tothe invention, it is possible to construct both cannulas 3, 4 with adiameter of a maximum of 1.3 mm. Since there is a quasi-nonthermalprocess taking place with the radiation of laser energy, in contrast toultrasonic phacoemulsification, the irrigating liquid need not be usedfor cooling and can accordingly be supplied by the cannula 3 in aspatially separate manner.

In a second embodiment example which will be described in the followingwith reference to FIG. 3, a switchable directional valve 16 is arrangedin the feed lines between the handpieces 5 and 6 and theirrigating-aspirating unit 9. On one hand, this directional valve 16 isconnected with the feed line 10 coming from the infusion pump 11 andwith the feed line 7 leading to the suction pump 8. On the other hand,the directional valve 16 has two outputs 17 and 18 and two inputs 19 and20.

As is further shown in FIG. 3, the handpiece 5 is connected with theoutput 17 and also with the input 19 similar to the handpiece 6connected with the output 18 and the input 20. The connection 21 at thehandpiece 5 branches off via branch 22 into two line paths, one of whichis connected with the output 17 via a feed line 23, while a second isconnected with the input 19 via a feed line 24.

In the same way, the connection 25 of the handpiece 6 branches, via abranch 26, into two line paths, one of which is connected to the input20 via a feed line 27, while a second is connected to the output 18 viaa feed line 28.

The directional valve 16 is connected with a foot switch (not shown inthe drawing) by means of which the directional valve 16 can be switchedin such a way that the flow from feed line 10 flows selectively tooutput 17 or output 18 and the feed line 7 for suction is selectivelyconnected to input 19 or input 20.

When a first valve position of these two possible valve positions isselected and the foot switch is correspondingly actuated, the output 17is connected, via feed line 23, to the handpiece 5 and rinsing liquid issupplied via the cannula 3. At the same time, the handpiece 6 isconnected to input 20 via branch 26 and feed line 27 in this first valveposition, wherein the ablated core material is sucked out through thecannula 4 and reaches the suction pump 8 via directional valve 16 andfeed line 7. Laser energy is supplied through a fiber tip 14.1 insidethe cannula 4.

When the operator intends to work with the core material proceeding fromthe opposite side of the eye lens, it is possible to actuate the footswitch and accordingly move the directional valve 16 into the secondvalve position in which the through-flow connection between feed line 10and output 17 is severed and, in its place, a connection is producedbetween feed line 10 and output 18. The through-flow connection betweeninput 20 and feed line 7 is likewise interrupted and, in its place, aconnection is made between input 19 and feed line 7.

The rinsing liquid is now supplied by the infusion pump via feed line 10through the directional valve 16 and its output 18, through feed line 28and branch 26 into the handpiece 6 and into the cannula 4 which isintegrated in handpiece 6, and from the distal end of the latter to thetreatment site.

At the same time, aspiration is carried out with handpiece 5, since itscannula 3 is connected with suction pump 8 via branch 22, feed line 24,input 19, directional valve 16 and feed line 7.

In this connection, a fiber tip is also associated with handpiece 5 forsupplying laser energy and is arranged inside the cannula 3. This fibertip can be connected with the laser source via a light-conducting fiber14.2, for example. Accordingly, energy can also be introduced into thecore material via handpiece 5, the core material can be ablated andsucked out through the cannula 3 as was described.

When the fiber tip is temporarily not in use in the respective handpiece5, 6, it can be retracted into the respective cannula 3, 4 according toan option of the invention, as is indicated by way of example in cannula3. This does not impede the introduction of rinsing liquid.

In some case it is advantageous when the branches 22, 26 are outfittedwith non-return valves which prevent liquid that has already been suckedout from returning to the eye unintentionally when switching thedirectional valve 16 or immediately after switching. In the simplestcase, the non-return valves are constructed as freely movable flapswhich contact valve seats in a sealing manner in the event of backed upliquid or reflux and accordingly prevent the reflux.

In preferred constructional variants, one of the two handpieces or, insome cases, both handpieces, can be coupled with mechanical auxiliaryinstruments, for example, to fix, mobilize or divide the lens or lensparts. Accordingly, for this purpose, no separate auxiliary instrumentsneed be inserted into the anterior chamber; rather, the requiredhandling can be carried out with the handpieces which are outfitted inthis manner.

FIG. 4 shows a selection of auxiliary instruments. For example, FIG. 4a)shows loops for holding, FIG. 4b) shows hooks for holding, and FIG. 4c)shows auxiliary instruments for gripping. Further, auxiliary instrumentscan be provided for cutting (scissors) and/or for splitting the corematerial (knives), for protection (protective shield), or also forillumination (fiber ends). Auxiliary instruments of this kind are knownfrom the prior art and therefore need not be described in more detailherein.

This technique of phacoemulsification which is applicable with theinstrument according to the invention has the advantageous result thatthe incisions in the cornea can be made substantially smaller than inthe prior art. In this way, fewer losses of aqueous humor and rinsingsolution are achieved during the operation, which, apart from thereduced requirement for rinsing solution, results in a reduced liquidvolume and accordingly in gentle treatment of the tissue surfaces of theanterior chamber, especially the endothelial layer of the cornea.Moreover, because of the small incisions, there is a reduced risk ofastigmatism being induced by the operation. Faster postoperative visualrehabilitation is also possible with incisions of this size.

The construction of the medical instrument for laser phacoemulsificationwith two handpieces according to the invention enables bimanualphaco-techniques which, apart form the above-mentioned advantages, alsoallows the operator greater flexibility in intraoperative handling.Using the emulsification principle which can be carried out with thisinstrument, the operator can remove the cataract through substantiallysmaller incisions in the cornea than was possible in the prior art. Thelens can accordingly be emulsified and aspirated while in the capsularbag and it is no longer necessary to open the capsular bag throughcapsulorhexis.

As was shown in the preceding, it is possible by means of this handpieceto carry out the operative steps at the eye with substantially smallerincisions in the cornea than was possible using handpieces previouslyknown from the prior art. Accordingly, this handpiece can beadvantageously utilized in connection with medical operative proceduresin which elastic material is introduced beneath the cornea for purposesof forming intraocular lenses (IOL). The prerequisite for these methodsof injectable intraocular lenses is phacoemulsification with very smallincisions.

While the foregoing description and drawings represent the presentinvention, it will be obvious to those skilled in the art that variouschanges may be made therein without departing from the true spirit andscope of the present.

What is claimed is:
 1. A medical instrument for phacoemulsification withwhich the biological tissue of a lens of the eye is ablated by theintroduction of energy, the ablated product is sucked out through anincision in the cornea, and the intraocular pressure is maintained bysupplying an irrigating liquid, comprising: two cannulas for sucking outthe ablated lens material and for supplying the irrigating liquid; atleast one device being provided for the introduction of energy throughlaser radiation; said two cannulas being enclosed by separate handpieceswhich are movable relative to one another; one of said handpieces withthe first cannula communicating with a suction device via a feed line;the other of said handpieces with the second cannula communicating witha supply device for the irrigating liquid via another feed line, andwherein each of the two handpieces and accordingly each of the twocannulas can be connected to the suction device and to the supply devicevia the feed lines, wherein there is provided in the feed lines betweenthe cannulas and the suction device and supply device a switchabledirectional valve by which, in a first valve position, the first cannulais connected with the suction device and the second cannula is connectedwith the supply device and, in a second valve position, the secondcannula is connected with the suction device and the first cannula isconnected with the supply device, and wherein the first cannula isconnected with the directional valve via two feed lines, the secondcannula is connected with the directional valve via two other feedlines, and the directional valve is connected with the suction devicevia a feed line and with the supply device via another feed line,wherein a feed line connected with the first cannula or a feed lineconnected with the second cannula can be connected to the suction devicevia a feed line or connected to the supply device via a feed lineselectively by the directional valve.
 2. The medical instrumentaccording to claim 1, wherein each cannula has a connection, wherein theconnection of the first cannula is connected with the two feed lines viaa branch and the connection of the second cannula is connected with bothfeed lines via a branch.
 3. The medical instrument according to claim 2,wherein the branches are integrated in the respective handpiece.
 4. Themedical instrument according to claim 1, wherein the directional valveis connected with a foot switch and can be switched selectively into thetwo valve positions by actuating this foot switch.
 5. The medicalinstrument according to claim 1, wherein each cannula is assigned to oneof the separate handpieces, wherein the two handpieces are movablerelative to one another and are designed ergonomically to be used by theoperator with both hands.
 6. The medical instrument according to claim1, wherein at least one of the handpieces comprises, apart from thecannula, the device for introducing energy through laser radiation,wherein this device is preferably constructed as a fiber tip.
 7. Themedical instrument according to claim 1, wherein a fiber tip is arrangedinside the cannula or the cannula at least partially, wherein the lightexit face of the fiber tip is enclosed by the outlet opening of therespective cannula.
 8. The medical instrument according to claim 1,wherein a fiber tip is displaceable within the cannulas in the directionof flow.
 9. The medical instrument according to claim 1, wherein thefirst cannula and the second cannula have the same diameter in the rangeof magnitude of 0.8 mm to 1.3 mm.
 10. The medical instrument accordingto claim 1, wherein the first cannula and the second cannula havedifferent diameters within the range of 0.8 mm to 1.3 mm, wherein thefirst cannula is larger than the second cannula.
 11. The medicalinstrument according to claim 1, wherein an infusion pump is provided assupply device and a suction pump is provided as suction device, eachdevice being connected with a controllable irrigating-aspirating unit.12. The medical instrument according to claim 1, wherein an Er:YAG laseris provided as energy source.
 13. The medical instrument according toclaim 1, wherein the handpiece with the first cannula and/or thehandpiece with the second cannula are/is outfitted with auxiliaryinstruments for holding, gripping, turning, pushing, cutting, splitting,protecting or illuminating the tissue at the treatment site.
 14. Themedical instrument according to claim 1, wherein auxiliary instrumentscan be connected with the handpieces selectively and alternately by anattaching mechanism.
 15. The medical instrument according to claim 1,wherein auxiliary instruments are arranged at the handpieces so as to beretractable.
 16. The medical instrument according to claim 1, whereinauxiliary instruments are arranged at the handpieces so as to bedisplaceable on a guide path.
 17. The medical instrument according toclaim 1, wherein a device for cleaning the cannulas, the feed linesand/or the branches is provided in at least one of the two handpiecesand serves to eliminate clogging when needed.
 18. The medical instrumentaccording to claim 1, wherein a device for cleaning is constructed as aspiral which is displaceable in the direction of flow.
 19. The medicalinstrument according to claim 1, wherein at least one of the twohandpieces is outfitted with a coupling mechanism for a device forsupplying substances for injectable intraocular lenses.
 20. The medicalinstrument according to claim 1, wherein connections are provided in thefirst cannula and/or in the second cannula, which connectionscommunicate, via the coupling mechanism, with a device for supplyingsubstances for injectable intraocular lenses.